In the dark with my 250, jumpstart yes, kick no

[Robertehv]

Good evening fellow xr fans,

 

I recently bought a 1991 xr250r.

Couldn't get it running with the kicker, jumpstarting did the trick.

Earlier this week I got it running by kicking, about 20 kicks..

Today no such luck.

Any ideas someone?

 

 

[1972RedNeck]

Do you know the XR starting procedure?

[dlock5]

Have you clean the carb?. Did you change elevation?, maybe it was jetted wrong to begin with.

[Robertehv]

Carb was cleaned twice, bike ran ok last week, only elevetion change was riding it out of the garage...?

 

It's just that I can't get it running with the kickstart.

[RockyMTN-Ryder]

Here's how I start mine. When cold. Choke on full. Turn the idle thumbscrew about 3 or 4 half turns to increase the idle. Do about 3-4 slow priming kicks until I start to get pressure on the Kickstarter near the top. Hold it. Pull in my de-comp lever once and let go. Kickstarter should drop maybe an inch with your foot on it. Let Kickstarter return to top. Then drop the hammer with a good kick. Keep repeating the priming kicks and decomp lever until it starts. Mine usually starts in 1-3 kicks. Each bike is different. This works awesome for me.

[XRalways]

Wow thats quite the procedure. Back when I had my 91...just kick. 2/3 kicks and she fired up

My '97 xr250 project that hasnt run in 5 years started after 7 good kicks. No fancy procedures.

IMO, if it doesnt start with ease, there is something not right.

[RockyMTN-Ryder]

But.
A kickstart bike that starts in 1-3 kicks is an easy starting bike and doesn't have any issues. Nothing fancy about knowing your bike and how it starts.

Glad your bike starts in 7 kicks.

Do you have some advice that will help the OP with the issue at hand?

[ThumperCurtis]

Being a new owner I had to figure this out with my XR400. Read some threads and finally got a good procedure to get it started.

1. Turn gas on and set Choke lever at 1/2

2. kick over 3 times with decomp open then release lever - this should prime the bike for firing

3. slowly kick over the engine until it reaches TDC - you'll know when because it will be the most resistance on the kick starter

4. With one strong kick the engine should fire - NO THROTTLE or you will flood out the engine (then it take about 20 kicks to start)

5. Once idling open choke fully an let idle for 15-30 sec to warm up

6. SLOWLY apply throttle as to not flood the engine and then it should operate fine

 

This may be a good starting point and you can develop your own starting process. Hope it helps.

[cpetz24]

Tight valves. 

Pilot jet could be off.

Is it an old spark plug? Had that happen before.  Plug looked fine, but had a weak spark.   Try a new plug, it's easiest and cheapest to try.  

The "Starting procedure" is not necessarily needed if you have the jetting correct.  I would say that finding TDC will help.  I've never had a bike where that didn't, but all the choking, and priming, and holding your tongue JUST right is just a band aid for something else.  

My XR has always started within the first 3-5 kicks cold, unless you let it sit for over a month or two, then it may take some persuading, but needless to say it always fires up.  

 

[Robertehv]

OK, so I got it started, new spark, some valve adjustment and learning to find tdc and exact choke settings did do the trick.

 

Still, it doesn't idle well.

Please check this clip on youtube, any ideas?

 

 

[Trailryder42]

Had you ever done a valve adjustment before? Want to be sure you know the proper setup. Setting crank at TDC on the "compression" stroke.

What adjustment did you make? How far off were they?

I see the choke is off. Does this video take place after the bike is warmed up?

Have you ever checked the intake manifold oring? If its bad or pinched, It can cause rough idling and it's a culprit a lot of folks don't think of..

When you say "jumpstarting" did the trick, did you mean "push or pull starting"?

 

 

[Robertehv]

Thanks for your reply Trailryder.

 

The bike has been running for almost an hour when I filmed it, took it for a little testdrive in the neighbourhood. Choke is off after about 1 minute after starting.

I am quite sure I checked the valves at TDC. The valves had some play when I checked. I read that when the inspection marks show and there's play I should be at TDC on the compression stroke. But I will check again just to be sure.

The clearance was not far off to start with.

Lost in translation, yes, I meant the push start.

The puffing that you hear, can that be valve induced?

 

Any help is appreciated.

 

[Trailryder42]

You know you're on the compression stroke because all 4 valve rockers will have wiggle in them. Also, if a measurement is way out of spec, like more than a couple of thousandths of an inch, you better go around 1 turn on the crank back to TDC and check gaps again.

You know, before measuring or making any adjustment on the right exhaust valve, you need to make sure the manual decomp mechanism at the head is adjusted properly and that you have the proper amount of slack take up at the handlebar lever. And that it's still ok AFTER valve adjustment. And you adjusted them to:

Intake: .05mm (.002" inch)

Exhaust: .08mm (.003" inch)

Right?

Who cleaned the carb? "Cleaned the carb" means different things to different people. Was the fuel screw removed and that passage cleaned and verified that the washer and oring was present and in good condition? Verified the screws tip was intact and not broken off? A dirty passage and bad /missing oring have been the cause of more headaches than you know.

Edited March 28, 2017 by Trailryder42

[Robertehv]

Thanks for your reply. I'm a bit puzzled how and where the free play should be. Bike only has the kickstart decompressor fitted.

If I move the kickstart down  it has a free play of about 2 inches before the triangle that makes the decompression cable move goes to work.

At the head I notice that when the cable starts moving it immediately moves the bracket that is connected to the cam.

 

 

Any thoughts on this?

[Trailryder42]

Are those videos taken with the engine set to TDC on the compression stroke? That's how the engine needs to be set up to know if the amount of travel in the mechanism is right or not.

[Robertehv]

No, just random, let me check that again day after tomorrow. I'll be back!?

[Robertehv]

Well, no tinkering with the auto decomp but a new check of the airmixture screw, looks good.

Since I pulled the carb, took a look behind the o-ring on the intake manifold

 

Ordered a new one, hopefully it's here by Saturday, my birthday=tinkerday!

[Trailryder42]

Where's the washer in that fuel screw picture? Clean the screw tip too.

Was the intake manifold oring flat as a pancake?

[Robertehv]

Darn, I thought I saw something fall off my bench! Look for it or get a new washer tomorrow. That tip was clean when I put it back in last time. I'm guessing the air leak and the popping in the carb fouled it.

O-ring is nice and flat still. I'll be reusing that again.

 

After taking the manifold off I tried it on the carb and it should seat a whole lot better than it did on the bike. I'll put the carb on the manifold first and than reinstall it. 

 

I'll be back.

[Trailryder42]

3 hours ago, Robertehv said:

 

O-ring is nice and flat still. I'll be reusing that again.

 

After taking the manifold off I tried it on the carb and it should seat a whole lot better than it did on the bike. I'll put the carb on the manifold first and than reinstall it. 

 

 

Sorry, I didn't mean for it to sound like the manifold oring being flat is a good thing. They're round when new. With age it develops the flat shape.

When I take my carb off, I leave the manifold attached to the carb. I take the 3 manifold bolts out, loosen the rear carb clamp and it all comes out as an assembly out the left side.